Mean occupation function of high-redshift quasars from the planck cluster catalog

Abstract

We characterize the distribution of quasars within dark matter halos using a direct measurement technique for the first time at redshifts as high as z~1. Using the Planck Sunyaev-Zeldovich (SZ) catalog for galaxy groups and the Sloan Digital Sky Survey (SDSS) DR12 quasar data set, we assign host clusters/groups to the quasars and make a measurement of the mean number of quasars within dark matter halos as a function of halo mass. We find that a simple power-law fit of log 〈N〉 = (2.11 ± 0.01) log(M) – (32.77 ± 0.11) can be used to model the quasar fraction in dark matter halos. This suggests that the quasar fraction increases monotonically as a function of halo mass even to redshifts as high as z~1.